The present invention provides a flat-panel type color cathode ray tube which has the favorable focusing characteristics and can shorten the total length thereof. The color cathode ray tube includes an evacuated envelope which is constituted of a panel 1 which has a diagonal effective diameter of approximately 51 cm, a neck 3 which houses an electron gun 10 and a funnel 3 which connects the panel and the neck. The electron gun 10 includes a cathode, a first electrode, a second electrode, a focusing electrode and an anode electrode. Assuming the equivalent radius of curvature in the X direction of an inner surface of the panel 1 as Rix and the equivalent radius of curvature in the Y direction of an inner surface of the panel 1 as Riy, the distance Lm between the cathode and a screen-side end portion of the focusing electrode is set to 37 mm≦Lm≦45 mm.